A system for pretreating sample conveys a sample rack, on which a sample tube is mounted, to each unit and pretreats a sample. Plugged sample tubes that can be set in a sample rack charge unit generally include a rubber-plugged sample tube, a resin-plugged sample tube, and a seal-type-plugged sample tube. Unplugging process in an unplugging unit must be carried out according to the type of a plug.
A conventional unplugging unit is an exclusive unit conforming to the type of a plug of a plugged sample tube, and basically it cannot treat a mixed group of sample tubes having different types of plugs. Therefore, in a system for pretreating sample having a conventional unplugging unit, a plugged sample tube to be processed must be selected from among the above types. If it is required to use the mixed group of sample tubes at any cost, plural unplugging units should be prepared in an identical system, which is unrealistic from the viewpoint of a space and a cost.
Consequently, when a user introduces a system for pretreating sample, the user needs in advance to select a plugged sample tube to be used from the group including a rubber-plugged sample tube, a resin-plugged sample tube, and a seal-type-plugged sample tube, and it is difficult to comply with user's request to use the mixed group of sample tubes. Further, in an inspection center or the like that collects and processes sample tubes delivered from plural hospitals and others, human workloads have been heavy because of such operation as interchanging samples into a sample tube that can be used in the system for pretreating sample.